Acoustic imaging means which employ mechanically scanned transducer means are well known as shown, for example in the following U.S. Pat. Nos: Klahr, 3,805,596; Rosauer, 3,547,101; Flaherty et al, 3,480,002; Spencer et al, 3,765,229; Walther, 3,585,851 and ; Clynes, 3,323,512. Some prior art arrangements are not adapted for rapid back and forth linear movement required for real-time imaging which is particularly useful in medical diagnosis. Other arrangements are bulky, take up much space, and are not readily adapted for use at different parts of the body. Still other prior art arrangements employ linear or sliding bearings which operate with higher friction than the pivoting joints employed in the present arrangement.